Moisture-proof flanged hub type connector



Nov. 25, 1958 L. J. CURRAN MOISTURE-PROOF FLANGED HUB TYPE CONNECTOR Filed Jan. 25, 1956 5 N U m MM MM M6 4 [J w u I 0 Z Y B M United Statesatent Oflfice 2,862,040 Patented Nov. 25, 1958 MOISTURE-PROOF FLANGEDHUB TYPE CONNECTOR Louis J. Curran, Los Angeles, Calif.

Application January 23, 1956, Serial No. 560,606

3 Claims. (Cl. 174-51) My invention relates generally to connectors forconnecting an electrical conduit to a housing wall, and moreparticularly to an improved connector of the flanged hub type.

In electrical wiring, the practice of using a flanged hub type connectorfor connecting electrical conduits to housings such as switch boxes,connection boxes, electrical cabinets and the like, is well known. Theconduit is threaded into the hub end of the connector and the connectorflange is then bolted to the housing wall. Such a connection is easy toperform and inexpensive.

Difiiculties arise, however, when it is desired to make the connectionmoisture-proof. If, in accordance with usual practice, a gasketapproximately the same shape as the flange is placed between the face ofthe flange and the housing wall, the connection will leak moisturearound the bolt holes. If, to prevent this, gaskets are placed aroundthe ends of the bolts, continuity of the electrical I ground circuitbetween the conduit and the housing is interrupted because the gasketsact as insulators.

Efforts have been made to avoid these difficulties by providing outwardextrusions around the openings in the housing wall so that upontightening of the connector bolts, a seal is formed between the flangeface and the extrusions which minimizes moisture leakage and stillmaintains the electrical ground circuit. This process is costly and notentirely satisfactory.

Accordingly, it is a major object of my invention to provide an improvedflanged hub type connector with means for forming a moisture-proofconnection and still maintaining continuity of the electrical groundcircuit. It is another object of my invention to provide means forforming such a connection which obviate the necessity of providingextrusions around openings in the housing wall.

It is a further object of my invention to provide means for forming sucha connection which may be incorporated into a standard flanged hub typeconnector with a minimum of modifications.

It is still another object of my invention to provide means for makingsuch a connection which are easier to use and less expensive thanprevious methods.

These and other objects and advantages of my invention will be apparentfrom the following detailed description thereof, and from an inspectionof the accompanying drawings, in which:

Fig. 1 is a perspective view of a housing with one embodiment of myinvention attached to the top thereof;

Figure 2 is a partially sectioned side view of a preferred embodiment ofmy invention shown connecting an electrical conduit to a housing wall;

Figure 3 is an enlarged, perspective view of the bolt gasket shown inFigure 2; and

Figure 4 is an enlarged, perspective view of the scarfing washer shownin Figure 2.

Referring now to the drawings, and particularly to Figure 2 thereof, thenumeral 10 indicates generally a flanged hub type connector having a hub11 with a threaded bore 12 for receiving an electrical conduit 13. Anoutwardly extending flange 14'is adjoined to one end of the hub 11 andhas bolt holes 15 near its outer circumference for securing theconnector to a housing wall 16. The threads in the bore 12 have aninwardly convergent taper to provide a moisture-proof, ground circuitmaintaining connection between the hub 11 and the conduit 13. The boltholes 15 have axes parallel to the axis of the bore 12 and aconvergently tapered conical counterbore 17 at the end adjacent the hub.

To secure the connector 10 to the housing wall 16, bolts 18 are providedwhich fit through the bolt holes 15, and suitable openings in thehousing wall 16 and are thereafter engaged by nuts 19. Thread tighteningthenuts 19 onto the bolts 18 draws a face 20 of the flange 14 intoengagement with the outside of the housing wall 16.

In order to make the connection between the connector 10 and the housingwall 16 moisture-proof, a face gasket 21 approximately the same shape asflange face 20 is provided for positioning between the flange face 20and housing wall 16. This gasket forms a moistureproof seal around thecircumference of the flange 14, but does not prevent leakage of moisturethrough bolt holes 15. For this purpose, bolt gaskets 22 are provided.These gaskets 22 have an internal bore 23 large enough to snugly receivethe shank portion of bolts 18, and a conically tapered outer surface 24adapted to seat in counterbore 17 in such manner that a small portion 25of the outer end protrudes from the counterbores. When the gaskets 22are engaged by the heads of bolts 18 and deformably compressed againstthe conical seating surface of the counterbore 17, they are entrappedbetween the bolt shanks and the seating surface thereby forming aneffective seal between the bolts and the flange. The protruding portions25 expand over the outer rim of the counterbore 17 aiding in the seal.

To maintain continuity of the electrical ground circuit, annual washers26 are provided, which have scarfing teeth 27 attached at theirperiphery and positioned approximately perpendicular to the body of thewasher. Two of these washers are located on the shank of each of thebolts 18, one between the bolt head and the bolt gasket 22, and a secondadjacent the nuts 19. The outer circumference of the washers 26 islarger than the maximum outer surface diameter of the gaskets 22 so thaton the washers positioned adjacent the bolt heads the scarfing teeth 27,which are directed towards the flange 14, extend over the protrudingportion 25 of these gaskets to engage the surface of the flange. Thescarfing teeth 27 on the washers adjacent the nuts 19 are directedtoward the housing wall 16 to engage its inner surface.

In operation, an electrical conduit 13 is threaded into the bore 12 insuch a manner as to give a moistureproof, electrically-groundedconnection as previously described. The connector 10 is then secured tothe housing wall 16 by fitting bolts 18 through the bolt holes 15 inflange 14 and thereafter passing the bolts through suitable openings inthe housing wall for engagement by the nuts 19. When the nuts aretightened onto the bolts, the face gasket 21 is compressed betweenflange face 20 and housing wall 16 and bolt gaskets 22 are compressedbetween the heads of bolts 18 and counterbores 17. A moisture-proofconnection is thereby established between the electrical conduit 13 andthe housing wall 16. Thread tightening the nuts 19 on bolts 13 alsoforces scarfing teeth 27 on the washers 26 into the surfaces of theflange and housing wall, thereby establishing an effective electricalgrounding connection between the electrical conduit 13 and housing wall16.

While I have shown and described a preferred form of my invention, it isobvious that changes may be made therein. For this reason I do not wishto be limited to the particular form or arrangement of parts hereindescribed and shown, but rather to the scope of the appended claims.

Iclaim:

l. A connector for connecting an electrical conduit to a housing wallcomprising: a hub having an inwardly convergent, taper threaded bore forreceiving anelectrical conduit, thereby establishing a moisture-proof,electrically-grounded connection between said hub andsaid electricalconduit; an outwardly extending flange on one endof said hub having aface surface perpendicular to the axis of said bore for engaging ahousing wall; means defining holes near the outer circumference of saidflange, said holes having an inwardly convergent conical seating surfaceat the end adjacent said hub; a bolt and nut for passing through saidhole and securing said flange to said housing wall; a conically taperedbolt gasket having an axial bore for snugly receiving the shank of saidbolt, and a conically tapered outer surface for engaging said seatingsurface, said gasket thereby providing a moisture-proof seal betweensaid bolt and said seating surface when compressed therebetween; anannular face gasket having an outer circumference shaped similarly tothe outer circumference of said flange, and being positioned to becompressed between said face surface and said housing wall therebyestablishing, in conjunction With said bolt gasket, a moisture-proofseal between said flange and said housing wall when said bolt and nutare tightened to secure said flange to said housing wall; a firstannular washer having a periphery greater than the periphery of saidbolt gasket with scarfing teeth projecting therefrom at an angleapproximately parallel to its longitudinal axis, said washer beingmounted on said bolt shank in limiting engagement with said bolt headand between said bolt head and said bolt gasket with said scarfing teethpositioned to project over the periphery of said bolt gasket and toengage and scarf the outer surface of said flange when said bolt and nutare tightened to secure said flange to said housing wall; and a secondannular washer similar to said first washer mounted on said bolt shankadjacent said nut with scarfing teeth positioned to engage and scarf theinner surface of said housing wall when said bolt and nut are tightenedto secure said flange to said housing wall; said first and secondWashers thereby forming an effective electn'cal ground connectionbetween said flange and said housing wall through said bolt.

2. A connector for connecting an electrical conduit to a housing wallcomprising: a hub for receiving a conduit; means for establishing amoisture-proof, electricallygrounded connection between said hub andsaid conduit; a flange on said hub having a bolt hole therethrough, saidbolt hole having a conically tapered seating surface; a bolt extendingthrough said bolt hole and having a nut for securing said flange to ahousing wall; a bolt gasket mounted on said bolt having a surfacegenerally complementary to said seating surface, and thereby providing amoisture-proof seal between said bolt and said seating surface whencompressed therebetween; a face gasket positioned to be compressedbetween said flange and said housing wall, thereby forming, inconjunction with said bolt gasket, a moisture-proof seal between saidflange and said housing wall when said flange is secured to said housingwall by said bolt and nut; a first washer mounted on said bolt adjacentthe head thereof and having a periphery greater than said bolt gasketwith scarfing teeth which extend over said bolt gasket for engaging andscarfing said flange when said flange is secured to said housing wall bysaid bolt and nut; and a second washer mounted on said bolt adjacentsaid nut with scarfing teeth positioned for engaging and scarfing saidhousing wall when said flange is secured to said housing wall by saidbolt and nut; said washers thereby forming an effective electricalconnection between said housing wall and said flange through said bolt.

3. A connector for joining electrical conduit to a housing wall having ahole therein, including: a hub for receiving a conduit therein; a flangeextending radially from an end of said hub and having a holetherethrough, said hole having a tapered enlargement forming a seat atone end thereof; bolt means extending through said hole; a resilientdeformable gasket mounted on said bolt and having an external surfacegenerally complementary to said tapered seat and extending outwardtherebeyond; a washer mounted on said bolt between said gasket and anend thereof, and extending beyond the periphery of said gasket; scarfingteeth on said washer positioned to engage the surface of said flange;means associated with said bolt means to secure said flange to saidhousing wall, compress said gasket into fluid tight engagement with saidbolt and seat and bring said scarfing teeth into engagement with saidflange; and scarfing means operatively associated with said securingmeans for making electrical contact between said bolt and said housingwall.

References Cited in the file of this patent UNITED STATES PATENTS2,097,713 Ashley Nov. 2, 1937 2,179,476 Andrus Nov. 14, 1939 2,235,429Henry Mar. 18, 1941 2,454,897 Trowbridge Nov. 30, 1948 2,476,074 UngerJuly 12, 1949 2,503,169 Phillips Apr. 4, 1950 2,508,655 Silverrnan May23, 1950 2,597,081 Goodhue May 20, 1952 2,778,868 Stinger Jan. 22, 19572,783,295 Ewing Feb. 26', 1957

